This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:    3GPP third generation partnership project    AGCH access grant channel    BCCH broadcast control channel    BSC base station controller    BTS base transceiver station    CCCH common control channel    DL downlink (BS to MS)    DSL digital subscriber line    EDGE enhanced data rates for GSM evolution    eNB evolved node B    GERAN GSM EDGE radio access network    GSM global system for mobile communication    LTE long term evolution of UTRAN (E-UTRAN)    LTE-A LTE advanced    M2M machine-to-machine    MBMS multimedia broadcast multicast service    MCS modulation and coding scheme    MS mobile station    MTC machine type communications    PBCCH packet BCCH    PRACH physical random access channel, packet random access channel    RACH random access channel    SIB2 system information block type 2    TBF temporary block flow    UE user equipment    UL uplink (MS to BS)    UTRAN universal terrestrial radio access network
Machine type communication (MTC) equipment refers to a category of user equipment (UE) that performs machine-to-machine (M2M) communication without user intervention or manipulation. One or more MTC devices are used to sense and collect data by detecting and measuring information. Illustrative examples of sensed data include temperatures, seismic intensities or water quantities. The detected and measured information is collected at a server (MTC server) configured to manage the MTC devices. Various services are provided to users on the basis of such information. The users receive services via the MTC server on the basis of the information reported from the MTC devices.
A communication path may be established between the MTC devices and the MTC server using a wired network, a wireless network, or any of various combinations thereof. Examples of wired networks include telephone lines, DSL (Digital Subscriber Line) and optical communication lines. Wireless networks may include any of various types of mobile phone networks. Use of a wireless network is advantageous in that it provides enhanced flexibility regarding the placement of individual MTC devices.
Typical wireless communication systems are optimized for mobile phones and such systems may be inefficient in the context of an MTC device that provides a data sensing service specific to M2M. For instance, a mobile phone is required to regularly check paging from a network side so as to receive an incoming call for voice communication addressed to the mobile phone. On the other hand, in the case of an MTC device without a voice communication function, the MTC device does not need to always remain in a ready state for receiving paging, and in fact this level of readiness is not necessary. Furthermore, MTC devices may be installed at remote locations scattered throughout a widespread area where user contact is infrequent. For this reason, the MTC devices may be designed to use a limited amount of electric power from battery cells or batteries, to thereby minimize power consumption and provide an enhanced operational life. The electric power consumed by a wireless interface used for communication should not he ignored.
Illustrative applications for MTC devices include, but are not limited to, smart metering, e-health, fleet management, bridge monitoring, object and person tracking, and theft detection, Smart meters report status information and measurements of electricity, gas, heat, water, or fuel consumption to a central station that gathers this information for billing each user. Typical features of MTC may include low mobility, large numbers of devices, small and sometimes infrequent data transmission, high reliability, time-controlled operation, and group-based communication. Some applications, such as meter reporting, are delay tolerant, whereas other applications require low latency, such as emergency services. It is expected that some service providers using MTC devices, such as electricity utilities, would require small messages to be sent on a frequent basis. This frequent messaging may be required when it is desired to control one or more grid parameters of an electrical power grid to implement a smart grid. However, existing wireless networks were designed to carry mobile phone traffic and do not expect to receive the short and ‘instant’ messages produced by the MTC devices. As a result, problems may arise due to the large signaling overhead that would be generated by a relatively large number of small messages.
It is expected that, over the next several years, the number of MTC devices on a typical wireless network will significantly exceed the number of mobile phones on the network. This projection implies that MTC traffic will consume a considerable amount of radio resources and may have the potential to degrade the performance of mobile phone traffic. A high volume of MTC messages will also degrade the user experience of human subscribers using web browsing and other non-real time services. If a large number of MTC devices connect to a network to receive or transmit data, congestion of the wireless network may be expected.
At present, MTC devices are supported at the physical layer using the global system for mobile communication (GSM) where inexpensive devices are widely available. With the widespread introduction of long term evolution (LTE) and the decommissioning of legacy systems, migration of MTC devices to LTE has been under investigation by many wireless network operators. One objective is to ensure that the cost of LTE-compatible MTC devices does not exceed the cost of legacy devices. Illustrative cost reduction techniques include reducing bandwidth, reducing the peak data rate, reducing the maximum transmit power. providing a single RF receiver chain, and providing half-duplex operation.
Optimization of MTC devices for use with wireless communication networks is an important issue that is currently being discussed in Release 12 of the Third Generation Partnership Project (3GPP). Pursuant to Release 12, low-cost MTC devices will likely be standardized. In the uplink (UL), these devices will be configured to support a reduced bandwidth for both RF and baseband, such as 1.4 MHz, for example. Thus, although the total system bandwidth may be, for example, 10 MHz, the MTC device is only able to use 1.4 MHz of the total bandwidth. This 1.4 MHz bandwidth is equivalent to six resource blocks.